Diagnosis: A species of Tropidolaemus, an Asian pitviper genus characterized by strongly keeled gular scales, a splenial that is separate from the angular (Burger 1971), and a unique dorsal scale microdermatoglyphic pattern of rounded cells that are strongly covered with longitudinal parallel lines and comb-like ridges (Hoge & Romano-Hoge 1983; striocristate pattern subtype sensu Price 1982, verified in ZMB 47809). Tropidolaemus laticinctus differs from all congeners by the following combination of characters: lack of pronounced sexual or ontogenetic differences in color pattern; presence of ornate head pattern with brown dorsal markings on green ground that are bordered by cream scales and are largest on the posterior head; wide brown pre- and postocular stripe that extends to lower side of head beyond angle of jaw; ornate labial pattern consisting of brown spots bordered by white or black, on green to cream ground color; conspicuous large brown spot extending from anteroventral corner of eye and posteroventral margin of pit to lower margin of supralabials; lower side of head with similar pattern as dorsal side of head, or mottled with numerous brown and black spots and streaks; dorsal body pattern consisting of broad brick-red to brown rings that may be incomplete dorsally or laterally and are about as wide as or wider than the cream to white interspaces; anterodorsal part of light interspaces of body pattern containing wide green bands; brown rings across belly connected midventrally to form midventral stripe (if brown rings incomplete ventrally, venter heavily spotted, with chessboardlike pattern); base of tail with whitish and brown rings, tip of tail lighter reddish brown with no or only indistinct bands. Tropidolaemus wagleri differs from T. laticinctus in having distinct sexual differences in color pattern, in females undergoing a dramatic ontogenetic color change from a bright green ground color to a largely black and yellow coloration with or without green components, in lacking an extensively patterned venter, and in lacking an ornate labial pattern. Juvenile females of T. wagleri further differ from T. laticinctus in having a dorsal pattern of very narrow red and white bands on bright green ground color and in lacking a dorsal head pattern; male T. wagleri of all ages differ from T. laticinctus in having a dorsal pattern of tiny red and white spots and in lacking a dorsal head pattern. Members of the T. subannulatus complex (including the types of Trimesurus [sic] philippensis Gray, 1842, Trimesurus [sic] subannulatus Gray, 1842, and Trigonocephalus wagleri var. celebensis Gray, 1849) differ from T. laticinctus in lacking a well-defined ornate head pattern with light-bordered dorsal markings and in lacking an ornate labial pattern, in lacking a ventral pattern of brown rings and/or midventral stripe, and in having a dorsal pattern of narrow bands or spots (vs. broad brickred to brown rings). Both sexes of sympatric members of the T. subannulatus complex differ from T. laticinctus in having a uniform or near-uniform green dorsal head color (fig. 8C in KUCH et al. 2007, vs. ornate brown head pattern), a narrower bluish (vs. wide brown) pre- and postocular stripe and largely patternless labial region (fig. 7C, vs. ornate labial pattern), the presence (vs. absence) of well-defined, black-edged ocelli on outer posterior margins of ventral scales (fig. 7C), and an otherwise uniform green to bluish green venter (vs. heavily patterned venter with brown rings and midventral stripe). Sympatric members of the T. subannulatus complex further differ from T. laticinctus in having narrow white and bluish or reddish bands or spots on uniform green ground color (fig. 11C, vs. broad brick-red to brown rings), and in having a tail pattern consisting of narrow bluish bands and wide green interspaces at the base and nearly equidistant, distinct narrow black and white bands on brownish to greyish ground towards the tail tip (fig. 11C, vs. well-defined, approximately equidistant light and brown rings on base of tail, and light reddish brown tail tip with no or only indistinct bands). Adult females of sympatric members of the T. subannulatus complex also differ from the adult female T. laticinctus illustrated by de Lang & Vogel (2005, 2006) in having a yellow to golden (figs. 7C, 11C; vs. reddish) eye color. In characters of scalation, the specimens of the available small series of T. laticinctus (N=5) differ from the examined T. subannulatus complex members from Sulawesi (N=16) in having a slightly convex anterior margin of the mental scale (vs. centrally concave when viewed from the same angle, or indented at the level of the tongue), and in having higher ventral scale counts (139–146 vs. 134–139, respectively). The females of T. laticinctus (N=3) also differ from the majority of examined T. subannulatus complex females from Sulawesi (11 of 13) in having a higher number of dorsal scale rows at midbody (25 vs. 23, respectively).